The speaker cabinet described in PTL 1 for example, has been known as the above-mentioned the speaker system. This speaker cabinet includes a first cabinet to which a speaker unit is affixed, and a second cabinet for forming a bass-reflex duct which is affixed to a bottom plane of the first cabinet. At the end portion of the first cabinet-bottom wall, there is provided an opening communicating with the bass-reflex duct.
The first cabinet is formed in a substantially rectangular parallelepiped shape, and includes three pairs of wall portions that are mutually opposing. Between these mutually opposing wall portions, there are respectively generated standing waves in each of which a wall portion serves as a node, and a central portion serves as an arc-shaped portion. Although the amplitude of typical standing wave takes the minimum value at the nodes of vibration, its sound pressure takes the maximum value at the same. As aforementioned, providing an opening at the end portion of the first cabinet-bottom wall is to provide the opening at a portion corresponding to a node of the standing wave, that is, the portion at which the sound pressure of the standing wave is maximized. Accordingly, there has been a concern that the influence of the standing wave with respect to sounds radiated through the bass-reflex duct becomes a serious matter, for an example. In particular, the provision of the opening in the bottom wall of the first cabinet elongated in a vertical direction shall lead to an occurrence of large peaks or dips at the low frequency range of the sound.